DFC is a descendant if DCS -- Directory Content Service, an experimentalservice that provides data access through shared memory mechanism of SysV IPC.

Both DCS and DFC are sponsored and intensively used by Kevin M. Liang in avery busy webserver enviroment.

DFC examines its config file for the list of directories, all regular filesin these dirs are loaded into shared memory areas. Programs that need thesefiles can access the areas by ftok(). Owner and group of the area are setafter the original file, and permissions are 0440.

Programs that access shared memory areas first must read sizeof( off_t )bytes of the area to determine its full length: